THINKFILMMany of the pro-choice activists who show up at protests in "Lake of Fire" seem to be mostly showing up for the cameras.

Lake of Fire (Unrated) ThinkFilm (152 min.) Directed by Tony Kaye. Now playing exclusively at the Film Forum in New York. THREE STARS

No issue in America is quite as divisive as abortion. And "Lake of Fire," an epic new documentary, is unlikely to help.

That's not, however, because it obviously favors one side or another. It's because director Tony Kaye -- who spent 17 years and all of his money making this movie -- favors the uncomfortable truth. And so he's taken his camera places and filmed things that neither side will want you see.

Yes, the anti-abortion crusaders are here, and few of them come off well (although Village Voice columnist Nat Hentoff talks, with some articulate insistence, about how human life is sacred at any stage). Too many go off on tirades against the "pagans" and "sodomites" arrayed against them. Others reveal a variety of frightening links, from the KKK to anti-government militias to mad bombers.

But many of the pro-choice activists who show up at protests seem to be mostly showing up for the cameras. Later, a punk singer dressed, briefly, in electrical tape performs with a wire hanger. Most shockingly, there's film of a woman receiving an abortion at 20 weeks. The camera goes in for a close-up as the doctor disposes of tiny, recognizably human limbs.

Kaye has probably finally given both sides something to agree on: Neither is going to be completely pleased with "Lake of Fire."

A ground-breaking maker of commercials and music videos in Britain, Kaye made his first Hollywood feature, "American History X," in 1998 -- and quickly flamed out, in fights with his leading man, his studio and any possible supporters he might have had. (A second project with Marlon Brando fell apart when Kaye greeted the star, inexplicably, dressed as Osama Bin Laden.) So Kaye financed this picture himself, shooting whenever he had the money (and declaring bankruptcy once along the way).

The result is, not surprisingly, a bit choppy, with the look of the picture -- blurry video, sleek black-and-white film -- changing constantly. An overdone score by Anne Dudley tends to overwhelm the images, while Kaye still remains too much the provocateur -- the punk-rock pro-choicer and the mad anti-abortionist who claims to have seen a Satanic baby-barbecue add nothing to this debate except noise.

Where this complicated, and ultimately overlong film is at its best is when it's at its simplest and most succinct -- following one woman through the day she decides to have an abortion.

The woman is both irresponsible (this is her fifth unplanned conception) and sympathetic (she suffers from depression and pain over a past abusive relationship). She is both at peace with herself (declaring she has no regrets before the procedure) and horribly wrought up (tearfully describing a "pain in her heart" minutes after the doctor has disposed of what a worker will only refer to as "the pregnancy").

And it is the equal power of those successive images that best explains why the two sides of this issue fight so fiercely. And why they will never, ever agree.